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July 2017 WINES&VINES 63 WINE EAST WINEMAKING tartaric acid addition treatment following primary fermentation and MLF for our Merlot and Cab- ernet Sauvignon wines in the 2015 vintage year. Bottled wines and treatments were evaluated at various ex- tension programs throughout 2016, though sensory analysis was not professionally quanti- fied or analyzed. For example, the first difference tasters noted in the Merlot was the color vari- ation among the three treat- ments. The Merlot wines treated with 4 g/L and 6 g/L tartaric acid had the most vibrant and red-hued color, which was visu- ally noticeable. The Merlot with a 2 g/L tartaric acid addition had a stronger purple-blue hue and appeared hazy. We did not q u a n t i f y t h e s e d i f f e r e n c e s analytically. A number of the winemakers' tasting notes commented on the enhanced perception of acidity in the Merlot that received a 6 g/L tartaric acid addition treatment. Many of these wine- makers agreed that the percep- t i o n o f a c i d i t y c o u l d b e manipulated with some deacidi- fication trials, and a few were willing to try the larger acid ad- ditions to the must/juice com- mercially in an effort to retain color post-malolactic fermenta- tion. In the Merlot with a 2 g/L tartaric acid addition treatment, the wine tasted noticeably flat and flabby, had burnt rubber- like flavors and was relatively unappealing. A few commented that it did not represent a typi- cal flavor profile associated with Merlot. An article by Shea Comfort, published in WineMaker Maga- zine in 2010, mentioned previ- ous research by the Australian Wine Research Institute indicat- ing high-pH musts did not retain as much "berry, fruit and spice characters" if the acid was ad- justed post-primary fermenta- tion compared to adjusting acid pre-fermentation. We noticed similar results in our wine trials: The 4 g/L and 6 g/L tartaric acid addition treatments pre-fermen- tation were a stark contrast to the 2 g/L addition treatment, as they had more noticeable red fruit flavors and less earthy characters associated with the flavor profile. As mentioned in Schneider (2012), the increased sourness also affected mouthfeel of the red wines, and many of them tasted thin or angular. This ap- proach to dealing with high- p o t a s s i u m p r o b l e m s w i l l obviously have an effect on the final wine style. However, sev- eral of these wines were later used for deacidification trials, and the results did provide some validation for commercial wine- makers to deacidify post-MLF to improve a wine's final quality and style. Several commercial wine- makers utilized pre-fermentation acid adjustments for the 2016 vintage with confirmed high po- tassium concentrations in their fruit. While the results of these adjusted wines have yet to be tasted, many winemakers expect dealing with high-potassium fruit may be a continued chal- lenge for future vintages. Denise M. Gardner is the extension enology associate at the Pennsylvania State University. She is currently based at the Montgomery County extension office in Collegeville, Pa. - B E C O PA D - Y E A S T & E N Z Y M E S - C R U S H PA D E Q U I P M E N T - S T E R I L E F I LT R AT I O N - W I N E R Y H O S E - O A K A LT E R N AT I V E S EASTERN WINE LABS Serving the Analytical needs of East Coast Wineries WWW.EASTERNWINELABS.COM Ph 609-859-4302 Cell 609-668-2854 chemist@easternwinelabs.com AOAC Member EasternWineLab_Mar09.qxp 1/22/09 9:47 AM Page 1 References for this article are available online at winesandvines.com. The 4 g/L and 6 g/L tartaric acid addition treatments pre-fermentation had more noticeable red fruit flavors and less earthy characters.